21.9.40 ${dsn_ret}
The DSN RET= value V8.10 and later
When sendmail receives a message via SMTP, it can also receive information about how it
should handle a bounce. That information is included as part of an envelope-sender
declaration:
RCPT To:
NOTIFY=how
Here, the RCPT To: command specifies an envelope recipient??™s address. Following that
address is the keyword RET=, followed by one of two possible keywords: full or hdrs (see
?§6.7.40 on page 247 for a more complete description of RET= and its keywords). The full
says to return the entire message, header and body, if the message bounces. The hdrs says
to return only the header if the message bounces.
When a RET= value is received as part of an SMTP transaction, sendmail saves a copy of
the keywords specified in the ${dsn_ret} macro. If multiple RCPT To: commands are issued
during a single SMTP session, and eachcommand lists a RET= value, eachcommand will
update the ${dsn_ret} macro in turn, overwriting the prior RCPT To: command??™s value.
The ${dsn_ret} macro is also given a value if the -R command-line switch(?§6.7.40 on page
247) is used to set the RET= value during mail submission.
For two examples of how this macro might be used in rule sets, see the ${dsn_notify} and
${dsn_envid} macros explained earlier.
This is the Title of the Book, eMatter Edition
Copyright ?© 2007 O??™Reilly & Associates, Inc.
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